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/**
* MIT/X Consortium License
*
* Copyright © 2015 Mattias Andrée <maandree@member.fsf.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "bus.h"
/**
* Statement wrapper that goes to `fail` on failure
*/
#define t(inst) if ((inst) == -1) goto fail
/**
* The name of the process
*/
char *argv0;
/**
* The command to spawn when a message is received
*/
static const char *command;
/**
* Spawn a command because a message has been received
*
* @param message The received message
* @param user_data Not used
* @return 1 (continue listening) on success, -1 on error
*/
static int
spawn_continue(const char *message, void *user_data)
{
pid_t pid = fork();
if (pid)
return pid == -1 ? -1 : 1;
setenv("arg", message, 1);
execlp("sh", "sh", "-c", command, NULL);
perror(argv0);
exit(1);
(void) user_data;
}
/**
* Spawn a command because a message has been received
*
* @param message The received message
* @param user_data Not used
* @return 0 (stop listening) on success, -1 on error
*/
static int
spawn_break(const char *message, void *user_data)
{
pid_t pid = fork();
if (pid)
return pid == -1 ? -1 : 0;
setenv("arg", message, 1);
execlp("sh", "sh", "-c", command, NULL);
perror(argv0);
exit(1);
(void) user_data;
}
/**
* Main function of the command line interface for the bus system
*
* @param argc The number of elements in `argv`
* @param argv The command. Valid commands:
* <argv0> create [<path>] # create a bus
* <argv0> remove <path> # remove a bus
* <argv0> listen <path> <command> # listen for new messages
* <argv0> wait <path> <command> # listen for one new message
* <argv0> broadcast <path> <message> # broadcast a message
* <command> will be spawned with $arg set to the message
* @return 0 on sucess, 1 on error, 2 on invalid command
*/
int
main(int argc, char *argv[])
{
bus_t bus;
argv0 = *argv;
/* Create a new bus with selected name. */
if ((argc == 3) && !strcmp(argv[1], "create")) {
t(bus_create(argv[2], 0) ? 0 : -1);
/* Create a new bus with random name. */
} else if ((argc == 2) && !strcmp(argv[1], "create")) {
const char *file = bus_create(NULL, 0);
t(file ? 0 : -1);
printf("%s\n", file);
/* Remove a bus. */
} else if ((argc == 3) && !strcmp(argv[1], "remove")) {
t(bus_unlink(argv[2]));
/* Listen on a bus in a loop. */
} else if ((argc == 4) && !strcmp(argv[1], "listen")) {
command = argv[3];
t(bus_open(&bus, argv[2], BUS_RDONLY));
t(bus_read(&bus, spawn_continue, NULL));
t(bus_close(&bus));
/* Listen on a bus for one message. */
} else if ((argc == 4) && !strcmp(argv[1], "wait")) {
command = argv[3];
t(bus_open(&bus, argv[2], BUS_RDONLY));
t(bus_read(&bus, spawn_break, NULL));
t(bus_close(&bus));
/* Broadcast a message on a bus. */
} else if ((argc == 4) && !strcmp(argv[1], "broadcast")) {
t(bus_open(&bus, argv[2], BUS_WRONLY));
t(bus_write(&bus, argv[3]));
t(bus_close(&bus));
} else
return 2;
return 0;
fail:
perror(argv0);
return 1;
}
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